Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

TBI to carb?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by BLzr4x4ngkid, Apr 9, 2001.

  1. BLzr4x4ngkid

    BLzr4x4ngkid 1/2 ton status

    Joined:
    Feb 18, 2000
    Posts:
    703
    Likes Received:
    0
    Location:
    Wichita, KS
    How hard is it to go from TBI to carbuerated? I know I will get a crap load of blah blah blah's, but I don't really need the fuel injection. It would be a different story if I had steep inclines to deal with and what not, but this is Kansas and all we have are flat mud holes. I just want to know what all will have to be changed, i.e. fuel pump, manifold, ect.

    "Don't hit me with them negative waves so early in the morning." Odd Ball--Kelly's Hereos
     
  2. BillyBob

    BillyBob 1/2 ton status

    Joined:
    Feb 23, 2000
    Posts:
    557
    Likes Received:
    1
    Location:
    Dumont, NJ
    FI good, carb bad, blah blah blah! j/k [​IMG] anyway, I would imagine that you would have to change what you mentioned, along with the distributor, since the ECM controls the timing. I dunno what else you need to replace, maybe even fuel lines.. someone else could probably go into more depth on this subject than me.

    <A target="_blank" HREF=http://billybob.coloradok5.com>http://billybob.coloradok5.com</A>
    If it ain't leaking oil, it ain't my truck![​IMG]
     
  3. CaptCrunch

    CaptCrunch 1/2 ton status

    Joined:
    Feb 2, 2001
    Posts:
    3,596
    Likes Received:
    1
    Location:
    Minnesota
    Basically if you have the elecronic timing and what not that would need to be changed (MSD box maybe), you could use the stock fuel pump amd lines setup. I ran a regulator to control the fuel pressure in one of my old cars. Ya changed to a 350 trans... if it has a lock up converter and was hooked up to the stock system that would need some modifying...Other then that... just the linkages as far as I know. Just wondering... why you dumping the FI?

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  4. wayne

    wayne 3/4 ton status

    Joined:
    Feb 1, 2001
    Posts:
    6,178
    Likes Received:
    0
    Location:
    Carlisle, Pa
    You will also need an intake. Me personally I would keep the TBI.

    <A target="_blank" HREF=http://jamonline.homestead.com/fromthegroundupK54x4/89Jimmy.html>http://jamonline.homestead.com/fromthegroundupK54x4/89Jimmy.html</A>
    <font color=blue>Happy Trails<font color=blue>
    <font color=blue>Wayne<font color=blue>
     
  5. Executioner

    Executioner 1/2 ton status

    Joined:
    Feb 22, 2000
    Posts:
    1,530
    Likes Received:
    0
    Location:
    Temp. Ft. Walton Beach Fl. home=Tucson, Az.
    If you do it let me know, I can trade you a good Q-Jet for your EFI.
     
  6. pcorssmit

    pcorssmit 1/2 ton status

    Joined:
    Jan 2, 2001
    Posts:
    1,346
    Likes Received:
    0
    Location:
    Denver, CO
    Ok, I'm sure everyone has already told you this is a horrible idea, but you probably don't care, so I won't waste my time.

    If you use the stock pump, you MUST use a return line. One easy method that I know works is to use a stock fuel filter for a '79 CJ7 with a 304. These have 3 fittings; supply, carb, and return line. We did this on my brother's '70 (w/in tank pump) when his Pro-Jection died.

    You need a new distributor, I suggest a large cap HEI for a similarly equiped, carburated (non-feedback) truck.

    You need a new intake manifold, a traditional four barrel will NOT bolt on to your heads. Buy a manifold for this conversion, or modify the 4 center bolt holes on a traditional one.

    Of course you already know the truck will never pass emissions, which you probably don't have to deal with (yet).

    I'm sure my brother would be more than happy to trade you for the parts you will need to do the swap.

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     
  7. CaptCrunch

    CaptCrunch 1/2 ton status

    Joined:
    Feb 2, 2001
    Posts:
    3,596
    Likes Received:
    1
    Location:
    Minnesota
    FP regulator hooks up to the return line and would control the pressure... 13 psi TBI pressure may be a bit much for a q-jet.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  8. pcorssmit

    pcorssmit 1/2 ton status

    Joined:
    Jan 2, 2001
    Posts:
    1,346
    Likes Received:
    0
    Location:
    Denver, CO
    13 psi is definitly too much for a carb. An aftermarket fuel pressure regulator would work fine (if I'm understanding you right). The stock regulator is mounted in the TBI, so it would be removed along with everything else. The filter I mentioned has an internal regulator of sorts, its just an easy way of doing it. A lot of the older CJs ran a return line with a carb, presumably to help prevent vapor lock.

    Pete

    '83 K5, 350 TBI (ex 6.2), 700R4, NP208, Dana 60/14 bolt, 4.56s, Detroits, 3" lift, 15-39.5x15 TSLs
    '97 Dodge 2500 4x4 CC LB Sport, Cummins 5 spd
     

Share This Page